<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/vue.js"></script>
</head>

<body>
    <div id='app'>
        <input type="text" name="mystr" id="mystr" v-model="mystr" />
        <button type="button" v-on:click="register">变大写</button>
    </div>
    <script>
        var app = new Vue({
            el: "#app",
            data: {
                mystr: ''
            },
            methods: {
                register: function() {
                    this.mystr = this.mystr.toUpperCase()
                },
            }
        })
    </script>
</body>

</html>